A liquid-crystal display device consists of a liquid-crystal panel composed of liquid-crystal display elements arranged in a matrix of rows and columns and a drive circuit that outputs drive signals to the liquid-crystal panel. Arranged on the liquid-crystal panel are signal lines that transmits drive signals to each liquid-crystal display element. The drive circuit displays images on the liquid-crystal panel by impressing drive signals that correspond to the display image on the liquid-crystal display elements of the liquid-crystal panel via these signal lines. FIG. 7 shows an example of a general liquid-crystal display device. As shown in the diagram, this liquid-crystal display device consists of control circuit 10, multiple source drivers 20-1, 20-2, . . . , 20-m (where m is a natural number and m>2), data bus 30, and liquid-crystal panel (LCD panel) 40. As stated above, LCD panel 40 consists of multiple liquid-crystal display elements arranged in rows and columns. For example, in an XGA-standard LCD panel, it consists of 1024×768 liquid-crystal display elements. That is, one row (line) of the LCD panel consists of 1024 liquid-crystal display elements, and the LCD panel as a whole consists of 768 lines of liquid-crystal display elements. One picture element of an image is displayed by liquid-crystal display elements. The drive circuit of a liquid-crystal display device consists of multiple source drivers 20-1, 20-2, . . . , 20-m. As shown in FIG. 7, the source drivers generate drive signals, which are analog signals, in accordance with the (n+1)-bit data D0, D1, . . . , Dn output via data bus 30, and output these drive signals to the signal lines. That is, each source driver 20-1, 20-2, . . . , 20-m has a digital-to-analog converter that converts the (n+1)-bit digital signals that are input to analog signals, and in accordance with the clock signal and other control signals input from control circuit 10 they convert the (n+1)-bit digital signals input via data bus 30 to analog signals and output them sequentially to the signal lines. A row of liquid-crystal display elements of LCD panel 40 are connected to each signal line. That is, each source driver 20-1, 20-2, . . . , 20-m outputs a display signal one line at a time to LCD panel 40 via the signal lines and outputs the drive signal for each line sequentially to LCD panel 40, thereby making it possible to display a one-frame image on LCD panel 40. FIG. 8 shows an example of a source driver that comprises a drive circuit. Each source driver 20-1, 20-2, . . . , 20-m shown in FIG. 7 has the same composition, so here we denote a general source driver by assigning symbol 20. Source driver 20 is composed so that silicon substrate 24 is sealed by resin on the surface of flexible printed wiring board (hereafter called for convenience flexible wiring board) 22, which is formed in, for example, a tape carrier package (TCP) and has flexibility. Also formed on the surface of flexible wiring board 22 is wiring 26, which consists of metal film having the prescribed pattern, and signal transmission between the outside and the integrated circuit (IC) formed on the silicon substrate is done via wiring 26. In FIG. 8, I1, I2, . . . , I8 and O1, O2, O3 are input-output pads that are formed on the surface of flexible wiring board 22 by metal film having the prescribed pattern. Also, i1, i2, . . . , i8 and o1, o2, o3 are signal input and output terminals on silicon substrate 24. The eight input pads and three output pads are shown here as an example, but in an actual source driver the number of input and output pads will vary depending on the number of input and output signals to be handled. As shown in FIG. 7, the drive circuit has multiple source drivers 20-1, 20-2, . . . , 20-m. Normally, an LCD panel is driven by about 6-12 source drivers. For example, in the case of an XGA-standard LCD panel, it has 1024 pixels per line and displays each pixel with liquid-crystal elements that emit the three colors R, G, B, so in order to display the pixels of one line it is necessary to drive 1024×3 signal lines. With, for example, 384 output signal lines per source driver, all the liquid-crystal display elements of one line can be driven by eight source drivers.
The demands made on drive circuits have grown ever more stringent in recent years as LCD panels have come to be made with larger size and higher precision. For example, with higher precision the number of pixels per line increases, and what is demanded is not just correspondingly more signal lines to drive them but also faster drive signals. In addition, a larger-size LCD panel means longer driving signal lines, greater load capacity of the drive circuit, and longer signal lines to transmit the pixel data to the drive circuit. With conventional drive circuits and their wiring methods there has been the disadvantage that the distortion of the transmission signal becomes greater, and it becomes difficult to supply signals having the expected waveform to each source driver. One cause of this arises due to the wiring formed between data bus 30 and the source driver shown in FIG. 7. Denoting the length of this wiring by Lsb, the distortion of the waveform increases with increasing Lsb. With regard to the signal lines of data bus 30, the signal lines formed between data bus 30 and the source drivers are formed in separate wiring layers on the substrate, so it is necessary to use a multi-layer wiring board. In order to shorten wiring length Lsb between data bus 30 and the source drivers, the source drivers could be arranged vertically as shown in FIG. 9. But because the source drivers that drive the LCD panel drive about 100–400 signal lines, it is necessary to expand the wiring region of the source drivers, and unlike a memory system, it is difficult to secure wiring region for a vertical arrangement such as that shown in FIG. 9, and normally this cannot be adopted.